Some paint levels better than others. My experience has been that paint that levels well one time, may not work the same every time.

A high quality brush will lay the paint on smoother and give less opportunity for brush marks. I like Purdy's brushes. They have a good smooth feel when painting. Keep it wet. Wiping a brush off on the side of the can constantly will cause the brush to get kind of stiff and lay tracks.

The way you paint also makes a difference. Long flowing strokes will eliminate many problems and will speed things up. When you start in a corner, brush it out however far it will go, then lap your brush marks back over the last part you covered.

With a sprayer, keep moving. A little fow-trol helps sometimes. It helps level out the finish. Keep the gun close enough to the work to avoid dry spray. Keep it far enough away to avoid runs. Keep it moving.

There are lots of things that help other people and much that helps me, that I haven't listed. Sanding between coats and laying it on thick will take a long time. To get a perfect job, it will take a while no matter how you do it.

This is how I paint. As Square says a good brush is required I also use Purdy. If your right handed start on the right or top load the brush well, paint a section and finish off with light strokes into the paint, then paint the next section. Just get the paint on and finish into the last section with long light stokes. Always paint into a wet section never paint into a dried area. If you are using good paint SW, BM etc. it should level nicely. Don't try to squeeze the paint put enough on but not enough that it will run. Also make sure you prep properly. Clean grease free. Primed if needed. No gloss finish will take paint well. If it is new wood use a good primer.

I never liked the snow. Except when I was a kid and I didn't know better. Kids don't get cold and sore and have to deal with it.
I do like the summers here in NY. But I look at it this way. We have a pool in NY that we can use all of 2 months. The rest of the time is has this black cover on it until the snow makes it white. In Florida I will have those two months or so that the weather is HOT and the rest of the year will be comfortable. I can live with that. I always said man was not meant to live in the frozen weather. At least not this man.